1. Field of the Invention
The present invention relates, in general, to a tuyere for an iron making furnace and, more particularly, to a tuyere for an iron making furnace, which can supply air, oxygen or a fuel, such as pulverized coal, into the iron making furnace, so that the charged fuel can be burned and iron ore smelted inside the furnace, and which has an increased life span.
2. Description of the Related Art
Generally, an iron making process is a process in which coke is used as a fuel and an iron ore is used as a raw material and these are charged into an iron making furnace through a charging inlet and hot air is introduced into the furnace through a blast passage of a tuyere provided in a lower part of the furnace, so that the charged coke burns and the iron ore is reduced and smelted, and thereby producing molten iron that is a hot melt.
In a conventional iron making furnace, the tuyere for introducing hot air into the furnace is typically made of pure copper. Although the melting point of pure copper is 1,083° C. which is a somewhat low melting point, cooling water is circulated in the copper tuyere at a high speed so that the copper tuyere can resist the heat of the hot air having a high temperature of about 1,200° C. which is being introduced into the iron making furnace through the tuyere.
To introduce hot air into the iron making furnace, the tuyere is provided in the wall of the furnace. Here, to realize a desired airtight structure of the tuyere regardless of the internal pressure of the furnace, the tuyere is typically installed to protrude inwards into the furnace after being combined with a tuyere cooler. Because the tuyere has an inward protruding structure as mentioned above, the tuyere must be prevented from being fused or damaged by heat inside the furnace. Accordingly, the tuyere is typically provided with a water cooling system, in which cooling water is introduced into the tuyere through an inlet and circulates through a cooling passage while cooling the tuyere prior to being discharged from the tuyere through an outlet.
Further, the conventional tuyere has a frusto-conical shape and is fabricated with a body unit and a tip part combined with the tip of the body unit, so that, when the hot melt flows down along the inner surface of the wall of the iron making furnace, the hot melt comes into contact with the tip part of the tuyere and may erode or damage the tip part. When the tip part of the tuyere has been eroded or damaged as described above, cooling water stops being supplied into the tip part so as to prevent the cooling water from flowing into the furnace, but the cooling water is supplied only to the body unit, thereby reducing the cooled area of the tuyere and reducing the cooling efficiency. Further, because the tip part is not cooled, the life span of the tuyere is shortened.